Great quality (but budget priced) 2D and 3D artwork you can use in your own games.
Game Development Crash Course
19 lessons and an hour of video get you started fast and free with Corona SDK game dev!
App Vault
Biz app developers - these help you create stunning apps in half the time while saving you tons of money you would have otherwise spent hiring designers.
Outlaw IDE
The #1 IDE for Corona SDK game and biz apps makes development even faster (free version available).
Mobile Game Dev Videos
8+ hours of video tutorials - see how to make games with Corona SDK!